Improvement in steam-valves



initrd Stairs @met l @mira WILLIAM A: SWEET, OF SYRACUS'E, NEW YORK.'

, Letters Patent No. 95,285, dated September 28, 1869.

' IMPROVEMENT IN STEAM-VALVES.

The Schedule referred td in Lhele'Lettes Patent and makingvpar't of the `sarna.

To all whom it lmay conce/rn:

Beit known-that 1, WILLIAM A'. SWEET, of the city of Syracuse, county of Onondaga, and State of New York, have invented a new and useful Improvement in Steam-Valves and I do hereby declare the following to be a suiciently clear and exact description of my invention, reference being made to the accompanying drawings, and letters thereon, that any one skilled in suchA mat-tels may'make and use the same.

Figure 1 is a view of the valvefchamhegshowing -theside where the steam is admitted',1,and the valve in working-position; A

Figure 2 is asectional view through A of iig..1'. Figure 3 is a sectional view through B" of g..1. f

Figure 4-is aside elevation of a valve detached from the seat, but `inounted4 upon the valve-stein or rockvshaft, and having my improvements added, as seen at The nature of my inventiiin consists in Iaiiixing a device to what is termed, in the mechanic arts, the segmental slide valve, in such ,a manner that all back pressnieupon the valve is'.V removed from 'the valvestemor rock-shaft, thereby permitting the stem to work freely upon its bearings, and thereby preventing all one-sided wearing of it and its bearings.

Like letters refer to like parts in all the views.

A is the valve-chamber, of any desirable form and size to suitthe style and capacity ofthe engine.

', B is the valve, the face of which is the segment of a circle whose centre is the axis of the valve-stein or rock-shaft D, and from which centre the seat of the valve B is also described, as best illustrated :it fig. 3.

Projecting from the face of the valve b b, are two wings o1` flanges, as at B B, fig. 3, between .whichthe' valve-stem, as at D, operates to move or rock tlievalve in opening or closing the port at E, iig. 3.

Said stem or shaft Dis made to fit snugly' between said flanges, to prevent any lost motion "iu operating the valve, but a suiiicientv amount'of freedom must be allowed to permit the valve to adjust itself to the seat in case the axis of the valve-stem should not coincide with the face of the seat.- i

To overcome any back pressure upon the valve that might lift it from its seat, springs have been introduced between the edge ofthe stem and' the bottom of the recess between the two flanges B B', and consequently,

all the back pressure of the valve was thrown u'pon'the Ahearings D D'of the valve-stem, and upon the sides of said bearings opposite "to the pressure, and the bearings are thereby gradually wom one-sided, and much expense is thereby 4necessarily incurred' in retting the several working-parts., since, by turning off 'the stems, the seats require to be hushed, 85o.

l'-.lo overcome yall such difficulties, I haveiutroduced the supplemental bearings G, which span the valvestem at the ends of the valve like a semicir'cular saddle, the convex surface of which is anarc whose centre is the axis of the valve-'stem or rock-shaft.

Said bearings or saddles are fitted into corresponding seats in the valve-chamber, and they are made suiiciently long to give abundant wearingfsurfaoe,

and against said surfaces the vback pressure of the valve is sustained, thereby completely relieving'the valve-stem or rock-shaft ot' all objectionable back .orA

onc-sided pressure.

A suiicieut amount of space is leftl between the plane face'srof these saddles, and the plane faces of the hearings of the valve, as at e e, to compensate for any diierences between the ends br' journals of the'valve and the seats, that may be caused by expansion or by the wearing of the faces, either of the .valve or its seat; and to prevent any noise by -the two surfaces striking together, springs are vinserted between them, as shown at e e. l

By such a construction and arrangement, the valve- 

